1. Field
Example embodiments relate to a magnetic layer, a method of forming the magnetic layer, an information storage device, and a method of manufacturing an information storage device. More particularly, example embodiments relate to a magnetic layer that can increase recording density, a method of forming the magnetic layer, an information storage device using magnetic domain movement and including the magnetic layer, and a method of manufacturing the information storage device.
2. Description of the Related Art
A flash memory is an example non-volatile memory, which has been used in various applications. Generally, flash memory has a low operating speed and short lifetime. To overcome such problems, other memories such as a magnetic random access memory (MRAM), a ferroelectric random access memory (FRAM), a phase-change random access memory (PRAM), a resistive random access memory (RRAM), etc., have been introduced. However, these other memories generally include and/or require switching elements connected to respective memory cells and thus, it is difficult to increase an integration degree of these other memories.
An information storage device using magnetic domain wall movement has been introduced. This information storage device is a new non-volatile information storage device in which a switching element connected to a memory cell is generally not used and/or required.
A minute magnetic region that constitutes a magnetic body is referred to as a magnetic domain. The direction of magnetic moments in a magnetic domain is identical. A magnetic domain wall is a boundary portion of a magnetic domain having a magnetization direction different from another magnetic domain. The magnetic domain wall has a desired and/or predetermined volume. The magnetic domain and the magnetic domain wall can be moved in a magnetic body by an external magnetic field and/or by a current applied to the magnetic substance. Accordingly, based on the principle of movement of a magnetic domain wall and a magnetic domain, a switching element for controlling access to a memory cell of a non-volatile information storage device may not be required.
In this regard, U.S. Patent Publication No. 2006/0120132 discloses an example of an information storage device using the principle of magnetic domain wall movement.
The information storage device (hereinafter, a conventional storage device) disclosed in U.S. Patent Publication No. 2006/0120132 includes a magnetic track perpendicular to a substrate. The magnetic track is divided into a storage track and a buffer track having a length similar to that of the storage track. This conventional storage device also includes a writing element and a reading element, which are adjacent to the center of the magnetic track. A plurality of magnetic domains are serially disposed in the magnetic track, and have magnetic domain walls therebetween. When the magnetic domains and the magnetic domain walls are moved, a writing operation or a reading operation is performed using the writing element and the reading element.
However, the magnetic track of the conventional storage device is formed of a soft magnetic material such as NiFe. In this regard, since the thickness of a magnetic domain wall in the soft magnetic material is thick, that is, several hundreds of nanometers (nm), increasing the recoding density of the conventional storage device is difficult. Also, since a large amount of current of about 1012 A/m2 is required to move a magnetic domain wall of a soft magnetic layer, the conventional storage device may have high power consumption. In addition, since only about ½ of the magnetic track is used as an available storage track, storing a large amount of information in the conventional storage device is difficult.